A designer may appear on the runway for only 30 seconds at the end of a show, sometimes merely poking her head out from backstage to wave (Miuccia Prada, Phoebe Philo), sometimes doing a full catwalk canter (Michael Kors, Alexander Wang). Either way, they know people will be watching — and Instagramming. “We dress up and dress down on purpose,” said Roksanda Ilincic, a London Fashion Week stalwart. “We are all making statements.”

Here, 11 designers reveal what they will be saying this season, and why.

Olivier Rousteing, creative director of Balmain, Paris Fashion Week

What “I always stick to skinny pants and boots, sometimes with a jacket or white shirt depending on my mood,” Mr. Rousteing said. The pieces come from the previous men’s wear show. He likes to show skin because, he said, it gives him confidence, especially now that he runs the length of the catwalk. (At first he would only step out from backstage.) “Jackets can be formal and bland, so showing skin balances the formality,” he said.

Why “You always remember the designers with a strong identity, like Yves Saint Laurent or Karl Lagerfeld,” he said. And there’s the commercial consideration: “Customers buy what I’m wearing after the show, and pop stars will want it, too.”

Lucky Charm A charm bracelet including an evil eye from a Bali beach and a watch given to him by his father. “When you go on a runway for 30 seconds and receive some love and some hate, you want protection and comfort,” he said.

Anna Sui walks the runway during New York Fashion Week in 2017.CreditVictor Virgile/Gamma-Rapho, via Getty Images

Anna Sui, founder of Anna Sui, New York Fashion Week

What Pieces specially made for her or ones from her collection that no one else has worn.

Why Ms. Sui used to dress down for her runway bow until her mother admonished her, saying before a show, “Why don’t you dress like a designer should?” Ever since, Ms. Sui has tried to “step it up,” she said. “I now like to celebrate a little bit more.”

When She changes in her office midafternoon, half an hour before she leaves for the show. Since last February, though, she tests her outfits in advance. At that time she was planning to wear a floral dress from her resort collection. “I tried it on and it was horrid,” she said. “It was too bright and flashy and would overshadow the collection.” At the last minute she put on a black fur coat from 2006 that she had in the office.

Special Ritual A glittery red pouch containing a carved coral ring her mother gave her for her first show and a black pearl ring her father bought for her from Hong Kong. “It is my good luck charm, which adds security,” she said.

Designer Tommy Hilfiger waves to the audience during New York Fashion Week in 2016.CreditTrevor Collens/Agence France-Presse — Getty Images

Tommy Hilfiger, founder of Tommy Hilfiger, New York Fashion Week

What Something from his own wardrobe that relates to his show, plus his vintage Levis. “For a nautical show, I’ll wear a nautical jacket, or if it’s more rock ’n’ roll, like last season, I’ll wear a black leather motorcycle jacket,” Mr. Hilfiger said. “They could be from five years ago, two years ago, but it’s what I wear in real life.

Why “I want to be comfortable and authentic,” he said. “I don’t want to wear a costume. I’m in my 60s and don’t want to look like I’m in my teens, so I wouldn’t wear things like skinny jeans. And I want to show that I am accessible; I’m a more regular person than a fashion snob.”

When The morning of the show or “maybe the night before if I’m traveling or it’s an early show.”

Designer Simone Rocha during London Fashion Week in 2017.CreditJohn Phillips/BFC, via Getty Images for The British Fashion Council

Simone Rocha, founder of Simone Rocha, London Fashion Week

What A black and white dress or a skirt with pockets and Nike sneakers or flats.

Why “The black doesn’t distract me when I’m working backstage,” Ms. Rocha said. “The skirt length allows me to move around, and I have always been a skirt rather than a trousers wearer, so this adds a level of femininity to a work uniform.” Pockets are “good for carrying my phones, headphones and lip balm.” Anything too decorative or fussy is avoided. “I like to be comfortable and feel like myself, so I don’t like being in brand-new clothes,” she said.

When She makes her final decision the night before the show, having had the chosen pieces dry-cleaned. “It’s one less thing to think about on the day of the show,” she said.

Tory Burch, founder of Tory Burch, New York Fashion Week

What “I like to represent the point of a collection, whether in a silhouette, print or color,” said Ms. Burch, who takes her bow in something from the collection, though not a look from the runway. Instead it’s one of the pieces that didn’t make it into the show.

Why It’s a nice way to acknowledge the efforts of the design team, and it’s good for sales. “When we post on social media, there is more impact from my outfit than from others, and it becomes the No. 1 print in the store,” Ms. Burch said.

When “A few days before the show, I pick a couple of things I like so I have options to choose from that morning,” she said.

Jason Wu during his show during New York Fashion Week in 2017.CreditDolly Faibyshev for The New York Times

What For his own label: Acne jeans, an A.P.C. tee or an Undercover sweatshirt and Adidas or Converse white sneakers. For Hugo Boss: a Boss black silk suit and tie, white shirt and brogues.

Why “At Jason Wu shows, I’m presenting as me because it’s my women’s wear label,” Mr. Wu said. “At Boss, I’m representing another brand, which has its own DNA and men’s suiting, so I wear something that represents them.” The stress of each season affects his style choices. “If I’ve pulled an all-nighter, I’ll want to be as casual as possible,” he said.

When “After 10 years, I’m comfortable in my own skin, so it’s last minute,” he said, adding that his wardrobe is all black, white and navy, he knows where everything is, and has multiples of everything, so it’s easy to choose an outfit at 6:30 a.m. on the day of his show.

Angela Missoni acknowledges the audience at the end of the Missoni men’s spring show in 2013.CreditGiuseppe Cacace/Agence France-Presse — Getty Images

Angela Missoni, creative director of Missoni, Milan Fashion Week

What “I like to wear certain things from my wardrobe, like my trench, shirt, trousers, with black as a base because it is easy and I can wear color with it,” said Ms. Missoni, who adds a sweater tied around her waist or draped over her shoulders for pop.

Why “I will wear old favorites that I haven’t worn for a long time or a new shape of trouser and shirt bought during the season,” she said.

When She starts thinking about her outfit a week before the show. “I’m not trying to impress the audience, but show the person I am, because if I am the face of the brand, I need to be believable,” she said. “I am working backstage, so I need to be at ease, but I also need reassurance because I will be running out in front of photographers and the most fashionable people in the world.”

Roksanda Ilincic at the Roksanda show during London Fashion Week September 2017 in London, England.CreditEamonn McCormack/Getty Images for The British Fashion Council

Roksanda Ilincic, founder of Roksanda, London Fashion Week

What Dresses from previous collections and high heels.

Why “It’s just who I am and what I normally wear,” Ms. Ilincic said. The high heels “make me more self-assured and dressed up,” she said. “Taking the bow is very intimidating, with everybody looking at me and judging my work.”

When “I dress like I feel the morning of the show, so if I feel like dressing up, like I did for the spring-summer collection (in a silky red dress and boots), I will do so,” she said. “If I feel like not dressing up, I wear the coat that I usually have backstage.”

Special Ritual Before every show, Ms. Missoni buys herself a present to wear on the day, like a charm to attach to her earrings or a ring.

Joseph Altuzarra, founder of Altuzarra, Paris Fashion Week

What Raleigh jeans, a tee, sweater and Adidas Stan Smith sneakers. His choices have stayed the same ever since his first collection in February 2009. This “gives consistency to how people see me,” Mr. Altuzarra said.

Why “I try not to look as if I’m trying too hard,” he said. “I wear similar things every day, which are simple, last forever, are a good price and are comfy. I don’t wear something too out there or too specific.”

When Mr. Altuzarra chooses his look the morning of his show. “I don’t want to feel too dressed up because it would be uncomfortable, and I don’t get a fresh haircut or have makeup done. It’s a continuation of who I am — someone who is down-to-earth.

Designer Mary Katrantzou acknowledges the applause after her 2017 spring show at London Fashion Week in 2016.CreditNiklas Halle’n/Agence France-Presse — Getty Images

Mary Katrantzou, founder of Mary Katrantzou, London Fashion Week

What Black Alaïa knit dresses with Prada boots or Mary Janes.

Why “When I’m making so many decisions about color and print for the show, I don’t want to do it for my clothes, so black is a psychological choice rather than an aesthetic one,” Ms. Katrantzou said.

When She changes into her outfit just before her show. “I phone my boyfriend during the day and ask him to bring any black dress he can find,” she said. “Last year he had to check the washing machine for what was clean, so we FaceTimed while he was at the washing machine to find the right piece.”

Special Ritual Lining up her boots or shoes alongside the models’ shoes so she can step into them as she comes out onto the runway. And clipping on crystal drop earrings, which she has carried in her Hermès tote all day. They “bring focus around my face and break away from the black,” she said.

Emilia Wickstead greets the crowd after presenting her collection during London Fashion Week in 2016.CreditNiklas Halle’n/Agence France-Presse — Getty Images

Emilia Wickstead, founder of Emilia Wickstead, London Fashion Week

What Pants and a top with flat shoes. Ms. Wickstead avoids wearing any piece from the collection she is sending down the catwalk. “I don’t need to look like the models,” she said. Instead I want to look confident in what I’m doing.” Cue Rochas point-toe Mary Janes and jeans she designed.

Why “It’s very daunting to run out on the runway with hundreds of people looking at you, so I have to know inside and out what I am wearing,” she said. She picks workwear favorites from her own collections.

Special Ritual Ms. Wickstead says a prayer before the show begins and always wears five gold bangles given to her by her grandmother. “She was like a mother to me because my mother was single and working, so they are my lucky charms,” she said.